$1-$Frame Load Analysis

The figure below shows a floor crane with electric winch with solid plastic wheels used for lifting and

moving loads. It has electric power capacity to lift a load $($P$).$ The concrete or sand counterbalance

weight $($W$)$ on the base prevents the crane from tipping forward when the crane is pushed by a horizontal

force $($F$)$ acting at a height $($H$)$ from the ground. For safety purposes, the drive system includes a torque

limiter coupled to a drum and allows the crane to lift no more than the working load $($P$).$

The following are given:

P$=3$ kN

F$=100$ N

Wc$=2\mathrm{.}7$ kN

w$=130$ N$/$m

a$=0\mathrm{.}8$ m

H$=1$ m

L$1=1\mathrm{.}5$ m

L$2=2$ m

L$3=1$ m $,$

L$4=0\mathrm{.}5$ m

L$5=0\mathrm{.}65$

The geometry and dimensions are known. The cable and hook are rated at $15$ kN $,$ with a safety factor

of $5.$ The $85$ mm diameter drum is about $20$ times the cable diameter. The crane frame carries the load

$P,$ counterweight $W_C,$ weights of parts $W_i(i=1,2,3,4,5),$ and the push force $F.$ The frame is made of

$b=50mm$ and $h=100mm$ structural steel tubing of $t=6mm$ thickness with weight $w$ Newton per

meter.

a$.$ Calculate the design load on the front and rear wheels.

b$.$ Calculate the factor of safety $n_t$ for the crane tipping forward from the loading.